71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
|
/**
|
||
|
|
* @license Apache-2.0
|
||
|
|
*
|
||
|
|
* Copyright (c) 2018 The Stdlib Authors.
|
||
|
|
*
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "stdlib/ndarray/base/minmax_view_buffer_index.h"
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Computes the minimum and maximum linear indices (in bytes) in an underlying data buffer accessible to an array view.
|
||
|
|
*
|
||
|
|
* @param ndims number of dimensions
|
||
|
|
* @param shape array shape (dimensions)
|
||
|
|
* @param strides array strides (in bytes)
|
||
|
|
* @param offset index offset
|
||
|
|
* @param out 2-element output array
|
||
|
|
* @return status code
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* #include "stdlib/ndarray/base/minmax_view_buffer_index.h"
|
||
|
|
* #include <stdint.h>
|
||
|
|
*
|
||
|
|
* int64_t ndims = 2;
|
||
|
|
* int64_t shape[] = { 10, 10 };
|
||
|
|
* int64_t strides[] = { 10, 1 };
|
||
|
|
* int64_t offset = 0;
|
||
|
|
* int64_t out[ 2 ];
|
||
|
|
*
|
||
|
|
* stdlib_ndarray_minmax_view_buffer_index( ndims, shape, strides, offset, out );
|
||
|
|
*
|
||
|
|
* int64_t min = out[ 0 ];
|
||
|
|
* // returns 0
|
||
|
|
*
|
||
|
|
* int64_t max = out[ 1 ];
|
||
|
|
* // returns 99
|
||
|
|
*/
|
||
|
|
int8_t stdlib_ndarray_minmax_view_buffer_index( int64_t ndims, int64_t *shape, int64_t *strides, int64_t offset, int64_t *out ) {
|
||
|
|
int64_t min;
|
||
|
|
int64_t max;
|
||
|
|
int64_t s;
|
||
|
|
int64_t i;
|
||
|
|
|
||
|
|
min = offset;
|
||
|
|
max = offset;
|
||
|
|
for ( i = 0; i < ndims; i++ ) {
|
||
|
|
s = strides[ i ];
|
||
|
|
if ( s > 0 ) {
|
||
|
|
max += s * ( shape[i]-1 );
|
||
|
|
} else if ( s < 0 ) {
|
||
|
|
min += s * ( shape[i]-1 ); // decrements min
|
||
|
|
}
|
||
|
|
}
|
||
|
|
out[ 0 ] = min;
|
||
|
|
out[ 1 ] = max;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|